problem with ensuremath construct

[fiolj]

Hi, pylatexenc 2.10 is failing with the construct:

LatexNodes2Text().latex_to_text(unicode_to_latex(LatexNodes2Text().latex_to_text(r"$\pm$")))

giving empty strings.
The conversion:

`LatexNodes2Text().latex_to_text(r"$\pm$")`

gives the expected result:
'±'

and the conversion to latex:
unicode_to_latex('±')
seems to be ok also:
'\\ensuremath{\\pm}'

but the last conversion:
LatexNodes2Text().latex_to_text('\\ensuremath{\\pm}')
fails, producing the empty string